1. Field of the Invention
The present invention relates to an electric printer using a processing unit for electrophotographic printing.
2. Description of the Prior Art
Recently, compact printers connected to personal computers and the like have begun using process units wherein a photoconductive drum, developing device and cleaner are contained in a single integrated unit. Use of the aforesaid type of process unit is extremely logical from the perspective of device maintenance inasmuch as the photoconductive drum, developing device and cleaner can be maintained by simply replacing the used unit with a new unit when, for example, the toner accommodated in the developing device is depleted. A problem of high device maintenance costs arise when the aforesaid type of disposable process unit is used, but this disadvantage is mitigated by the reduction in the cost of the unit produced by automated assembly and mass production of said process units.
On the other hand, JIS standards for large electrophotographic printers capable of printing A0 and Al sizes are limited to use in computer aided design (CAD) illustrations and the like. Thus, it is difficult to mass produce the aforesaid process units and achieve the resulting cost reduction, and rationalization of the use of said process units has yet to be realized.